This is a BULK lamp. It's a Coralife lamp without the retail packaging.

The Coralife 34 inch, 10K, 39 Watt T5 HO Fluorescent Lamps are 34 inches from end of pin to end of pin (for 36 inch fixtures/retrofits). These slightly bluish 10K lamps are typically used in tanks with corals, but can also be used with fish only tanks, and freshwater tanks with live plants.

The Coralife T5 bulbs will work in any T5 fixture, as long as you are using bulbs of the same wattage as those currently in your fixture. T5 bulbs come in two categories, HO bulbs (24W, 31W, 39W or 54W) and NOs (9W, 14W, 21W or 28W). T5s are 5/8" or .625" in diameter. Man Part# 80405.